Background
He was born on July 4, 1812 in Boston, Massachusetts, United States, where his father was a noted architect. His parents were Caleb and Sally (Willes or Willis) Pratt.
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Thomas Willis Pratt
Edit ProfileEducation
He obtained his elementary education in the Boston public schools, later attending the Rensselaer School (afterward Rensselaer Polytechnic Institute) at Troy, New York. During his school years, he spent all his spare time assisting his father in his work as architect and builder.
Career
While at Rensselaer, he showed such unusual aptitude for mathematics and the natural sciences that, despite his youth, he was offered a permanent position on the teaching staff of the school. He had, however, upon the advice of his father, already determined upon an engineering career, and refused the proffered instructorship to become an engineering assistant with the United States government on the construction of dry docks at Charleston, and Norfolk.
After a few years' experience on government work, Pratt turned to the field of railroad construction which, chiefly, was to occupy the remainder of his professional career. His first engagements were with the Boston & Lowell and Boston & Maine railways. In 1835 he became division engineer on the construction of the Norwich & Worcester, and subsequently superintendent of the road. He was successively engineer and superintendent of the Providence & Worcester (1845 - 47) and the Hartford & New Haven (1847 - 50) railways.
He became chief engineer of the Middletown Branch railroad, then chief engineer and superintendent of the New York & Boston, and finally, from 1871 to his death, chief engineer and superintendent of the Conway & Great Falls branch of the Eastern (later Boston & Maine) railway. In his work as engineer for these roads, he became especially interested in bridge construction, which field presented the most difficult technical problems confronting the railroad builder in Pratt's day.
Prior to about 1850, the mechanical action of trusses was imperfectly understood, and patented forms, laying claim to many real and fancied advantages, were common. Pratt's invention, patented April 4, 1844, claimed certain advantages in regard to detail, but the truss achieved no especial distinction until the advent of all-metal truss construction, for which the internal bracing of the Pratt truss is particularly well adapted. The popularity of the invention was so long deferred, however, that Pratt received little or no financial return from it.
His inventive genius was evinced by numerous other patents taken out by him; among these were patents for a new type of steam boiler, September 26, 1865; for an equalizer for drawbridge supports, February 22, 1870; for an improved type of combined timber and steel truss, April 1, 1873; for a new method of hull construction for ships, May 4, 1875, and for a new method of propulsion, June 1, 1875.
He almost never wrote technical papers or took part in technical discussions, either orally or in print; his occasional contributions to newspaper discussions invariably appeared under the nom de plume "Bruno. " From 1849 until his death he lived in Boston.
Achievements
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As a railroad and bridge builder, Thomas Willis Pratt ranked among the foremost of his time, but his greatest fame in engineering circles derives from his constraction of a number of important bridges, of which the largest and best known was one over the Merrimac at Newburyport, Massachussets. He is best known for his 1844 patent for the Pratt truss, which he designed with his father. He also had numerous other patents: a new method of propulsion, a new type of steam boilerand others.
Personality
Though one of the most gifted and highly esteemed engineers of his day, he was modest and reticent very nearly to the point of eccentricity.
Connections
Pratt was married between 1835 and 1840 to Sarah Bradford of Plainfield, Connecticut, by whom he had one son and one daughter.
